Variable condenser



ug- 12,' 1930` G. A. YANocHowsKl 1,772g598 VARIABLE CONDENSER Filed.June 271 i924 ummm-im r- Illlllllllll' Patented Aug. 12, 1930 UNITEDSTATES GEORGE Ai YANOCHOWSKI, OF LA GBAVNGE,

ILLINOIS, ASSIGNOR TO KELLOGG SWITCH- BOARD AND SUPPLY COMPANY, OFCHICAGO,'ILLINOIS, A CORPORATION OF ILLI- NoIs vARIABLn Appnation 1aedJune 27,

invention relates to condensers and has to do more particularly withvariable condensers with an air dielectric, such as are now in generaluse in radio or wireless receiving 5 sets, and an object of my inventionisthe provision of an improved condenser of the variable type, which isprovided with structural features which will facilitate assemblyA of acondenser of this type and, at the same time, provide anv improvedcondenser structure which# will permit the efficient operation ofi thesame and be of thelow loss type. l

The condenser of my invention is of the type in which the rotary plateelement is operatively located in position relative to the fixed platesof the'stator element so that the capacity of the condenser may be madeto vary in the desired manner, which of course,

is well understood by those skilled in the art.

One of the features of my invention is the means provided and the mannerin which I support andy space the conducting plates of the rotor elementto form asingle mountable unit, andalso the plates of the fixed orstator element of my condenser to form a single mountable unit.

vAnother feature of my invention is the provision ofavernier element formy condenser which consists in the provision of a suitable conductingplate which is loosely and rotatably supported on the 'rotatable shaftsupporting the rotor element of my condenser,

and also the provision of means for rotatably and vernierly adjustingsaid conducting plate on said shaft to obtain a better and fineradjustment of my 'condenser without disturbing the adjustable positionof the said rotor\ element.

Still a. further feature of my inventionv is the provision of frictionalmeans for maintaining the Vernier element of my condenser in itsadjusted position.

The above features as well as others, will be more s e criticallypointed out in the ensuing speci cation and appended claims, and for aclearer understanding of the same 1eference may be .had to theaccompanying drawings, inwhich like reference characters. in the severalviews denote like parts.

Referring to the drawings:

CONDENSER 1924. 4Serial No. 722,711.

l. Fig. 1 is a view in elevation of the condenser of my invention;

Fig. 2 is another view 1n elevation of the condenser of my inventiontaken from a dif-v ferent angle; Fig. 3 is a top plan View of Fig. 1;

Fig. 4 is a. view along the line 4-4 of Fig. l looking in the directionof the arrow;

Fig. 5 is a sectional view along the line 5-5 rotor elementofmycondenser, and also having the means provided for spacingA and se--curing the said plates lin position. l .1

Referring now in detailto my invention as illustrated in theaccompanying drawings, R is the rotor element andS is the statorelement, while V is the Vernier element of the condenser of myinvention.

Referring first to the stator element of my condenser the same comprisesa plurality of semi-circular plates 1 suitably formed of brass or someother suitable conducting material by a punching operation. Integrallyformed with each ofv the plates 1 arethree outwardly extending portions2, .each f of which is provided with a slot 3. The slots?) of the plates1 are adapted to be in alignment with each 'other when. the plates 1 arearranged one above the other. shaped recess 4 is provided. in each ofthe Spacing and supportingmembers 5 are provided, each of which isprovided with a plurality'of pairs of slots 6, there being as man pairsof slots 6 asthere arey plates 1. Each7 pair of slots 6 is of a size topermit the portion between the pair of slots 6 to fit into a slot 3 ofthe plate 1 while the slots 6 are of a An arcuate .g5 plates 1 forpurposes to be later pointed out.

size to receive the inner edges Sforming the I endsofthe said slot 3.A-To* assemble the plates 1 the same are placed in a suitable fix tureprovided for assembling purposes, and then the spacing and suportingmembers 5 y will be inserted into the s ots 3 of theplates 1 whilethe inner edges 3 of the ends of said 2 I La' slots 3 will protrudethrough the pairs of slots 6, and when the members 5 are engagingtheplates 1 as just pointed out, solder is applied to the protrudinginner edges 3 whereby said members 5 are soldered to said plates l in'the slots 3 of the protruding portions 2 of the plates 1, said plates 1and members 5 now 'forming a single mountable unit. The two spacingmembers 5 secured to the ends of the plates 1 are longerthan the othermember 5 and their free ends are turned over at right angles to the mainbody of said members, said turned over ends being provided with openingsand adapted tosupport the stator element S in its mounted position aswill be more clearly pointed out in the ensuing speciiication. Y

The rotor element R comprises a plurality of substantially semi-circularplates 8, each ot' which is provided with a reduced semi-4 circularportion 9 integrally formedtherewith and provided with an opening 10 forreceiving the rotatable shaft 11, the said plates 8 being stamped andsuitably formed out of brassor some other suitable material by apunching operation. Each platev 8 is provided with a pair of slots 12,formed in the semi-circular portion 9,-each of which is ot a size toreceive a spacing and supporting member 5 which is substantially thesame in construction as the members 5 of the stator element S. 'Eachmember 5v is provided with a plurality of pairs of slots 6',corresponding in number to the number of plates 8, said members 5 beingladapted to tit into the slots 12 while the end portions 12 of saidslots12 engage and protrude slightly throngh the said pairs of slots 6', andwhen the members 5 are engaging the slots 12 as just described solder isapplied to the protruding end portions 12 whereby said plates 8 andmembers 5 are secured together to form the rotor element R of myvcondenser. It will be seen that the plates 8 are separated from eachother since Vonly one-plate will engage a pair of slots 6,

said plates 8 being placed one above the other so that the openings 10in said plates are in alignment with each other. A diskmember 14 havinga hub portion 15 integrally formed therewith is'provide'd and is of asizeto t between the extending ends of the members 5 so that the centralopening 16 coincides with the aligned openings 10 in the plates 8,

I and when the disk member 14 is in this position solder is applied atthe point of engagement of said members 5 and said member 14 wherebysaid member 14 is secured to said members 5.

The Vernier plate element V comprises a substantially semi-circularplate 18 which has anintegrally formed extending member 19,

the said plate 18 and extending member being provided with an integrallyformed flange 20. The plate 18 is provided with a saucer shaped portion21 in the center of which isa ases suitable opening 22 :tor receivingthe reduced end 23 of a cylindrical member 24, the said reduced end 23being staked over to prevent the displacement of said cylindrical member24. The member 24 is provided with a central opening 25 and acircumferential groove 26 for purposes to be subsequently pointed out.

'lo assemble and operatively support the rotor element R and the statorelement S otl my condenser in position, a pair ot' mounting members 30and 31, suitably formed of brass or some other suitable material, areprovided. The mountingmembers 30 and 31 are sc-rred together andseparated from each other by means of the bridging members 30 which havetheir ends turned over and are secured to and between the members 30 and31 by suitable screws 31 which pass through suitable openings in themembers 3() and 31, insulating strips 32, and openings in the turnedover ends ot the bridging members 30' and then have screw threadedengagement with the nuts 33. The stator element is disposed between themounting members 30 and 31, as shown in F ig. 1, and is securedtherebetween to the insulating strips 32 by means of screws 29 whic passthrough suitable openings in the said insulating strip 32 and thenextend through the openings in the turned over ends of the spacing andsupporting members 5 and have screwthreaded engagement with suitablytapped nuts, whereupon the stator element S 1s secured to the strips32and supported between the mounting members 30 and 3l, and is insulatedfrom said mounting members by the insulating strips A cylindricalscrew-threaded member 34 is provided which has screw threaded engagementwith a.

suitably tapped opening 35 in the member 30 and is adjustable thereinand is held in its adjusted position byA a'nut 36. The rotor ele ment Ris now inserted between the mounting members 3() and 31 so that theplates 8 of said rotor element are disposed between the plates 1 of thestator element S, and the cone-shaped end of the hub member 15 fits intothe cone shaped portion of the central opening in the adjustablesmember34. The rotatable shaft 11 is now inserted through the central open-ling in the member 34, opening 16 in the hub member 15 and disk'14,aligned openings 10 in the plates 8, through the central opening 25 inthe member 24, and its concave end brought to rest in a suitable openingin the mounting member 31 and in engagement with the ball bearing 38.The ball bearing 38 is held in llll the rotor elementR may be adjustedrelative to the plates 1 of the stator element S by oper spring member39 is sufficient to maintain the hub member in constantengagement withthe member 34 whereby the rotor element R is w maintained inits-longitudinally adjustable position. A screw 43 extends through anopening in the spring member 39 and has screw-threaded engagement with atapped orifice in the mountmg member 31 for providing the right amountof tension on said spring member 3. The Vernier'plate member 18 andcylindrical member 24 are disposed between the end plate 1 of the statorelement S and the mounting member 31, the said member 24 tting looselyon the shaft 11' so that said shaft will rotate independently of saidmember 24. The member 24'and late 18 are maintained out of engagementwith the end plate 1 of the stator element S by means ofa spring member45 which has its one end secured to the mounting member 31 by a -pairofy suitable screws which have screw threaded engagement A'with suitablytapped o enings in the member 31, the other end of sai spring 30 member45 being bifurcated and adapted to fit around the cylindrical member 24kin the circumferential groove 26 of said member 24.

The bifurcated end of the 'spring member 45 f is distorted to provide apair of arcuate portions 46 which have frietional engagement with theface 47 of the groove 26 in the Vmember 24. The tension of the springmember is such as to maintain the end ofthe member 24 in engagement withthe mounting member 40 I31 and the Vernier plate 18 away from the endplate ofthe stator element S. The mounting plates 30 and 31 are sovdesigned that they protect the rotor, stator and Vernier elements frominjury. A

To rotate the Vernier plates 18 and member'24 on the shaft 11, a'rubberring member 50 is provided which is. suitably secured on a suitablecylindrical member 51, and a-rotatable shaft 52 is provided whichextends through a collar member 53, a suitable opening in the member 30,through the 'cylindrical member 51 and has its one end ref4 duced andadapted to fit into a bushing member 54, `said bushing 54 resting in anelonf gated slot 55 formed in the member 31. The

rubber ring 50 is adapted to be adjusted on the shaft 52 so that it willengage the `flange 20 -of the Vernier plate 18 and its extension 19 andwhen adjusted, a set screw 56 is rol6u tated into frictionalengagement-with the,

shaft 52 to hold the said rubber ring memberv50 and member 51 in theiradjusted position on the shaft'52. -The collar member 53 is securedonthe shaft`52 by a set screw 57 which has frictional engagement with saidshaft 52. As thefrubber ring member 50 is worn and reduced in size, dueto its frictional engagement with the iange 20 oi? the Vernier plate,the set screw 58 will be rotated and moved inwardly to move the bushingmember 54 in the slot 55, thereby moving the shaft to bring the rubberring 50 into better frictional engagement with the flange 20 of theVernier plate 18 to' overcome the wearingeifect of the rubber ring 50.

To mount my condenser in position on a suitable mounting panel the samemay be accomplished by means yof suitable screws which pass throughsuitable openings in the mounting panel'andV then have screw-threadedengagement with suitably tapped orilices in the members 59 which areintegrally formed with the mounting member 30., The

free ends .of the shafts 11, and ,50 extend through suitable o eningsinl the mounting panel, land the col ar member 53 engaging the panelprevents endvvisev movement of the shaft 52. Suitable control members.are secured on the shafts 11 and 52 for rotating said'shafts. v Y i 'Inoperating my condenser the operator grasps the dial secured to the shaft11 and rotates the same to adj-ust the rotor element R relative to thestator element S, and when adjusted the same is held in its adjustedposition by the frictional engagement of the hub member 15 andadjustable member 34. The recesses 14 in the plates 1 permit therotation of the rotor element R. -The operator now grasps the membersecured onthe shaft 52 and rotates the same whereupon the rubber ringmember 50 engaging the flange 20 will rotate the Vernier plate 18 toadjust the same relative to the end late of the stator element S,thereby effecting ay finer adjustment of my condensery as will bereadily understood by those skilled in the art. To limit the amount ofrotary movement' of the verj nier plate 18, a stop pin 60is provided andsuita 1y. secured to the mounting member 31 and adapted to be engaged bythe,y said Vernier plate k.18 to permit approximately only` 180 degreesof rotation of said plate 18. lhe Vernier plate 18 will be held in itsadjusted y osition by the frictional enga-gement of the ifurcated end ofthe spring member 45 and the face 47 ofthe circumferential groove 26 inthe cylindrical member 24` which will bear the said member 24 down onthe inner face of the supporting member 31.

Fromthe fore oing it will be at once seen that I have pro ucedacondenser V'which is simple in construction and inexpensive tomanufacture as practicallyl all of the parts 'are formed by a punching oeration. Also that` I have provided very ysimple and dependable meansfor supporting and separating the conducting plates of my condenser toform single mountableunits and which have .been referred to throughoutthe above description of my condenser as the rotor element and statorelement.

It will further be seen that I have provided a very neatly designedVernier plate which is rotatably supported on the same shaft whichsupports the rotor element of my condenser, and that simple means areprovided for effecting a minute adjustment of i. the said Vernier platerelative to the end plate of the stator element, thereby obtaining ainer and better adjustment of my condenser, and further, that simplemeans are provided for maintaining the vernier` plate element in itsadjusted position. Other features and advantages are obviously presentin my condenseras pointed out above and as will also be set forth in theappended claims.

Although I have described a particular embodiment of my invention, it isto be understood that I do not Wish to be limited to the exactstructure, as shown and described,

lbut that I intend to cover all changes and modifications which -maycome within the spirit and scope of the appended claims.

Having described my invention what Iv claim as nevi7 and desire tosecure by Letters Patent is l. A device of the class describedincludingr a rotor element comprising a plurality of conduct ing membershaving slots formed therein, a rotatable shaft forsupporting said rotorelement, means for longitudinally adj usting said rotor element on saidshaft, members provided Withslots' and arranged in pairs, said pairs ofslots adapted to register with the slots `in said conducting members 'sothat said second members will engage and rest 1n theslots 1nsaid-conducting members, the slots in said second member being the vsamesize as the thickness of said first members, said slots in saidconducting members being-the same size as the portion between oppositenotches of the other members so that the said members tit tight whenplaced together, and portions of said conducting members will engage andprotrude through the slots in said second members, said first and secondmembers being supported on each other-to form a single mountable unit,an auxiliary rotor element comprising a single plate, frictional meansengaging the periphery or said plate :tor rotating the same, and

means for adjusting the frictional relationship of said means and saidplate.

2. A device of the class'described including arotor element having aplurality of conducting plates, said plates being provided with slots,supporting-members provided with slots, said members adapted to engagethe slots in said plates, the slots in said second member being the samesize as the thickness ot' said iirst members,the portions of saidmembers between opposite slots being substantially the same size as theslots in said conducting plates so that the said plates and members'forma solid unit when placed together, and said plates adapted to engage theslots in said. supporting members, means for holding said plates andmembers in their assembled position to form a single mountable unit, ashaft for supporting said rotor element, means for longitudinallyadjusting said rotor element along said shaft as a unit, an auxiliaryrotor element comprising a single plate, trictional means engaging theperiphery of said plate for rotating the same, a rotatable shaft forsupporting said rictional means, and means for adjusting said shaft tovary the frictional engagement of said frictional means and said plate.

3. A device ot the class described including a rotor element, anauxiliary rotor element ter with and receive the end portions of one ofsaid first members forming a slot therein, and the portion ofthe memberAbetween said pairl ofslots adapted to engage the said slot in said onevfirst member, so that said first members are supported and separated bysaid second members, the slots insaid second member'being the Asame sizeas the thickness of said rst members, the portions of said membersbetween opposite slots being substantially the same size as the slots inthe first `member so that the said members form a solid unit when placedtogether.

e. A device of the class described including a rotor element and astator element, a shaft for rotatably supportiner said rotor element,means for longitudinally adjusting said rotor element relative to saidstator element, said elements each comprising a plurality of conductingmembers', each of said members being provided With a slot, anotherconducting member provided with slots arranged in pairs, a pair oi saidslots adapted to receive one of said first members .and'to permit saidother member to t into the slot provided in said one member, the slotsin t said second'member being the same size as the thickness of saidirst members, the portion of said second member between the pairs ofslots being 'substantially the same size as the slot in said firstmember so that the said members form a solid structure when placedtogether, the other of said members engaging the other pairs of saidslots in 'like manner, means for securing said members andv saidother'member together to form' a single mountable unit, an auxiliaryrotor .element iitailllwlml comprising a single plate, frictional meansengaging the periphery of said plate for rotating'the same, a rotatableshaft for supporting said frictional means, supporting members for saidshaft, and means for posi .tioning said shaft in one of said supportingmembers for adjusting said frictional means relative to said plate.

A device of the class described including a rotor element and a statorelement, a shaft for rotatably supporting said rotorelemeut, means forlongitudinally adjusting said rotor element relative to said stator elemeut, said elements each comprising a plurality of plates provided withopenings, another member provided With openings arranged in pairssaid'pairs of openings being uniformly spaced one from another, saidplate adapted to engage the pairs of openings in said member, and saidmember adapted to engage the openings in said plates,

Awhereby said plates are uniformly spaced :from each other, the openingsin said mem ber being substantially the same in 'size as the thicknessof said plates, the portion of said second member between vsaid pairs ofopenings beingsubstantially the same size as the opening in the firstmember so that the said members form a solid structure when placedtogether, means for securing said plates in their assembled positionagainstdisplacement, an auxiliary' rotor element comprising a, singleplate, frictional means engaging the periphery of said plate for ro?tating the same, a rotatable shaft for sup porting said frictionalmeans, supporting members forsaid shaft, and means for positioning saidshaft in one of said supporting members for adjusting said frictionalmeans relative to said plate.

6. A. device-of the class described includ-.

ing a pair of mounting members, a rotor element and a stator element, ashaft for rotatably supporting said rotor element, means forlongitudinally adjusting said rotor ele ment relative to said statorelement, said elements each comprising a plurality of conducting membersprovided With slots, supporting jmembers provided With slots uni-`formly spacedfrom each other, the said conducting members adapted t-oengage the slots in said supporting members and the said supportingmembers adapted to engage the slots in said conducting members,'wherebysaid members form a single mountable unit, the slots in said secondmember being the same size as the thickness of said first members, theportions of said supporting members between opposite slots beingsubstantially the same size as the slots in said conducting membersvsothat the said members:

j form a. solid structure when said mounting member engages the slots insaid conducting members, means including said supporting 5 'members forsecuringjsaid single mountable supporting members,v means co-operatingvvvith one of said supporting mem ers for longitudinally adjusting saidrotor element on said shaft, a Vernier plate element rotatably supportedon said shaft, a non-eonduetf ing ring member for engaging said Vernierplate element, another rotatable shaft for rotatably supporting saidring member, said ring member and shaft adapted to rotatably andVernierly adjust said Vernier plate ele; ment relative to one of theplates of said fixed plate element, and Ameans for adjusting said ringmember and said second shaft relative to said Vernier plate element.

8. A deviceof the class described including'a stator element, a rotorelement, a shaft for rotatably supporting said rotor element inoperative position relativeto said stator element means forlongitudinally adjusting said rotor element on said shaft, a, eonduct-4ing plate, means for rotatably supporting ioo said conducting plate onsaid shaft and in operative position relative to said stator element,means including a non-conducting rino* member supported on a secondshaft and3 adapted to engage the said conducting platefor rotatably andVernierly adjusting l said conducting plate relative to said statorelement, and s ring meanshaving a`bifurcated portion or engaging saidrst means for holding said first means and said conducting plate intheir adjusted position on said first shaft. I

9. A device of the i class described including a pair of mountingmembers, affixed plate element supported by said members, a rotor plateelement, a shaft for rotatably supportt ing said rotor plate element,means for longitudinally adjusting said rotor element on said shaft, aconducting plate, means for rotat-ably supporting said plate on saidshaft, means including a nonconducting ring member and a rotatable shaftfor rotatably sup porting said ring member, said ring mem, ber adaptedto engage the peripheral `edge of said conducting plate for Vernierlyadjusting said, conduct-ing plate relative 'to la plate of said fixedplate element, and spring means secured to one of said mounting membersand having a bifurcated portion adapted to ril and a rotatable shaft forrotatably and yernierly adjusting said conducting plate relative to aplate of said fixed plate element,

' spring means secured to one of said mounting members and adapted toengage said iirst lmeans to hold saidconducting plate in its adjustedposition, and stop means for limitiig the degree of rotation of saidconducting at'e. p 11. A device of the character described including astator element and a rotor element, a shaft for rotatably supportingsaid rotor element relative to said stator element, means for adjustingsaid rotor element longitudinally along said shaft, an auxiliary rotorelement adapted to be rotated concentrically with respect to said rstrotor element, an independently mounted rotary shaft frictionallyconnected to said second rotor element for operating'said second rotorelement, and means for adjust-ing said frictional connection of saidshaft and said second rotor element.

1Q. A device of the character described in cluding a stator element anda rotor element,

a shaft for operating Asaid rotor element,

means for longitudinally adjusting said ro tor element along said shaft,a second rotor element rotatable concentrically With re spect to saidstator element, an independently mounted shaft for rotating said secondrotor element, a. non-conducting ring member affixed to said secondshaft and having frictional engagement with said second ro- `tor elementfor rotating the same and means for adjusting said second shaft toregulate the degree of frictional engagement.

13. A device of the character described including a rotor element and astator element, a rotatable shaft for supporting said rotor element,means for longitudinally moving said rotor element along said shaft tospace said rotor and stator elements, an auxiliary rotor element,operating means including a member frictionally engaging said auxiliaryrotor element for operating the same, and means for adjusting saidfrictional member relatire to said auxiliary'rotor element.

14. A device of the character described including'a stator element and arotor element, a rotatable shaft for supporting said rotor element,means for longitudinal-ly moying said rotor element along said shaft tospace said rotor and stator elements, an auxp iliary iotor elementrotatable concentrically with respect to said stator element, meansincluding a frictionally engaging disk for operating said auxiliaryrotor element, and means for adjusting the degree of said frictionalengagement of the disk and auxiliary rotor element.

l5. A deviceof the character described including a pair of mountingplates, a stator element secured to said mounting plates, a rotorelement, a shaft supported by said mounting plates for rotating saidrotor element, means for longitudinally adjusting said rotor elementalong said shaft, an auxiliary rotor element rotatably mounted upon saidshaft, anauxiliary shaft independently supported by said mountingplates, a non-conducting ring member supported on said auxiliary shafthaving a frictional ,engagement with said auxiliary rotor element forrotating said auxiliary rotor element, and means for regulating thefrictional engagement of said ring member and said auxiliary rotorelement. v

16. A device of the character described including a pair of mountingplates, a stator element secured to said mounting plates, a rotorelement, a shaft supported by said mounting plates for rotating saidrotor element, means for longitudinally adjusting said rotor elementalong said shaft, an auxiliary rotor element rotatably mounted upon saidshaft, an auxiliary'shaft independently supported by said mountingplates for rotating Said auxiliary rotor clement, and adjust ing meansfor regulating the position of said auxiliary shaft relative to saidauxiliary rotor element.

i7. A device of the character described including a pair of mountingplates, a stator element secured to said mounting plates` a. rotorelement, a. shaft supported by said mounting plates for rotating saidrotor element. means for longitudinally adjusting said rotor elementalong said shaft. an auxiliary rotor element rotatably mounted upon saidshaft, an auxiliary shaft independently supported by said mountingplates for rotat-l 'mg said auxiliary rotor element, adjusting means forregulating the position of said auxiliary shaft relative to saidauxiliary rotor element. and spring means for holding said auxiliaryrotor element in its adjusted position.

i8. A device of the character described including a rotor plate having aflanged portion, a disk adapted to frictionally engage. said flangedportion of said plate to rotate the same. and means for regulating thefrictional engagement of said disk and said plate.

i9. A device of the character described in cluding a stator element anda iotor element` a shaft for operating said rotor element, means forlongitudinally adjusting said rotor element along said shaft, a secondrotor el lSO vifrvatee n ment rotatable lconcentrically with respect tomeans for longitudinally adjusting said rolsaid first rotor` element, anindependentl'- mounted shaft, mean". operated by said sha t in direct.Contact with said second rotor Ielemen't .to 4operate the same, springmeans adapted'to ,engage the end of said first shaft for maintaining itin its adjusted position and othersp'ring means adapted to engage thesaid second rotor element to maintain 1t 1n itsadjusted position. f

20. vA deviceof the character `describedi11 cluding a rotor element anda stator element,

said stator element com rising a plurality of v .conducting plates eachaving a plurality of extensions, a flat conducting stripy provided withpairs of slots, the portion of said Hat strip between the slots forminga pair being of a `size to it snugly into'saidslots.

Signed by me at'Chicago, in the County of Cook, State of Illinois, this25thday of June',y

GEORGE A. YANOCHOWSKI. ``75 an auxiliary rotor element, an operating-`member for said first rotor element', means for longitudinally adjustingsaidrotor ele# ment on said operating member, a second op-` eratingmember, a member controlled by said second oierating member directly incontact with sai auxiliary rotor element for operating the same, springmeans adapted4 to main- A tain said rotor element in its adjustedposition and a second .spring having a bifurcated portion adapted tomaintain said auxiliary rotor element .its adjusted positions.

21. A device of the character described including a stator element and arotor element,

a concentrically mounted auxiliary rotorl elef ment, a shaft for saidfir-st rotor element,

tor element on said shaft, an independently mounted shaft for saidauxiliary rotor elei ment, a device for said second shaft Adirectly incontactlwith said auxiliary rotor element for operatlng the same, andmeans for regulatingthe contactual engagement of said de- .forregulating the contactual engagement of said device and said auxiliaryrotor element. 23. A device of the character described including a rotorelement and a stator element,

arotatable shaft for supporting said rotor` element, said rotor elementcomprising a plurality of conducting members each Vhaving asemi-circular yextending said extending portion,'a at conducting striphaving a plurality of pairs of slots formed therein, said conductingmembers being of a thickness to fit snugly in said" notches, and

the portion between said pairs of slots being oav size to lit snuglywithin said notches in said xtending portion, and means forlongitudina'lly adjusting said iotor element on 'said shaft.

' 24. A device of the character described oluding a rotor elementiand astator element,

ortion, notches in4 l

